Evaporator, evaporation method and substrate processing apparatus

ABSTRACT

Disclosed are an evaporator, an evaporation method, and a substrate processing apparatus, which can increase the concentration of generated vapor of an organic solvent and efficiently heat the organic solvent. The evaporator includes a fluid tube, a liquid organic solvent supply device for supplying the organic solvent liquid to one end of the fluid tube, and heating units for heating the fluid tube. The fluid tube has a cross section that increases from the one end to the other end. When the organic solvent liquid supplied to one end of the fluid tube is heated, the organic solvent vapor is discharged from the other end of the fluid tube. The substrate processing apparatus includes the above-described evaporator.

This application is based on and claims priority from Japanese PatentApplication No. 2008-228752, filed on Sep. 5, 2008 with the JapanesePatent Office, the disclosure of which is incorporated herein in itsentirety by reference.

TECHNICAL FIELD

The present invention relates to an evaporator, an evaporation method,and a substrate processing apparatus, which evaporate a volatile organicsolvent, such as isopropyl alcohol (IPA), and more particularly to anevaporator, an evaporation method, and a substrate processing apparatus,which can increase the concentration of the generated organic solventvapor and efficiently heat the organic solvent.

BACKGROUND

In general, a fabricating process by a semiconductor fabricationapparatus mainly employs a washing method in which a semiconductor waferor a substrate, such as glass for LCD (hereinafter, referred to as a‘wafer’), is successively immersed in a washing tank containing awashing solution, such as a chemical solution or a rinse solution. Inaddition, a drying method is known that includes the application ofvapor, produced from a volatile organic solvent (e.g. isopropyl alcohol(IPA)), to a washed wafer surface, where the vapor is condensed oradsorbed, and the provision of an inert gas, such as N2 gas (nitrogengas), to the wafer surface to remove and dry the moisture on the surface(for example, refer to Japanese Laid-Open Patent No. 2007-5479).

In the drying method described above, when the vapor of the organicsolvent is supplied to a chamber housing a wafer, an evaporator is usedthat generates the organic solvent vapor by evaporating the liquid ofthe organic solvent by applying heat. For example, Japanese Laid-OpenPatent No. 2007-17098 discloses the aforementioned evaporator.

A conventional evaporator disclosed in Japanese Laid-Open Patent No.2007-17098 includes a heat source lamp, such as a halogen lamp, and ahelical fluid tube surrounding the heat source lamp, in which the fluidof an organic solvent to be heated flows. The liquid of the organicsolvent flows in the helical fluid tube, and is heated through theheating of the fluid tube by the heat source lamp, thereby generatingthe vapor of the organic solvent within the fluid tube.

In a conventional evaporator disclosed in Japanese Laid-Open Patent No.2007-17098, organic solvent liquid is mixed with an inert gas, such asN2 gas, and the mixed fluid of the organic solvent liquid and the inertgas is then sent to a fluid tube. Herein, the inert gas functions as acarrier gas. However, in such an evaporator, since the organic solventliquid sent to the fluid tube includes an inert gas, a problem exists inthat the organic solvent is diluted by the inert gas, and theconcentration of the organic solvent vapor generated within the fluidtube become lower.

SUMMARY

According to one embodiment, an evaporator for generating the vapor ofan organic solvent is provided. The evaporator includes a fluid tube, aliquid organic solvent supply device for supplying the liquid organicsolvent to one end of the fluid tube, and a heating unit for heating thefluid tube. The fluid tube has a cross section that increases from oneend to the other end. The liquid organic solvent is supplied to one endof the fluid tube and is heated to allow the vapor of the organicsolvent to be discharged from the other end of the fluid tube.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates an evaporator according to oneembodiment of the present invention.

FIG. 2 shows the configuration of the evaporator as shown in FIG. 1.

FIG. 3 schematically illustrates another configuration of a heating unitof the evaporator according to the present embodiment.

FIG. 4 schematically illustrates a still another configuration of aheating unit of the evaporator according to the present embodiment.

FIG. 5 schematically shows the configuration of a substrate processingapparatus according to one embodiment of the present invention.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. The illustrativeembodiments described in the detailed description, drawings, and claimsare not meant to be limiting. Other embodiments may be utilized, andother changes may be made, without departing from the spirit or scope ofthe subject matter presented here.

The present invention provides an evaporator and an evaporation methoddesigned to increase the concentration of organic solvent vaporgenerated within the fluid tube by preventing the inert gas from mixingwith the liquid organic solvent. According to the evaporator and theevaporation method of the present invention, the fluid tube has a crosssection that increases from one end to the other (that is, from theupstream to downstream side), and thus the organic solvent liquid,unmixed with the inert gas, is evaporated within the fluid tube. Eventhough the volume of the organic solvent increases, it is possible toimprove the thermal efficiency in various states (in the liquid state,the mixed state of liquid and vapor, and the vapor state). Therefore,the present invention provides an evaporator and an evaporation methodcapable of efficiently heating the organic solvent.

The present invention provides a substrate processing apparatus capableof shortening the drying time of the substrate and reducing the usageamount of the organic solvent. This is achieved by drying the substratewith a high concentration of the organic solvent vapor generated by theevaporator, which increases its adsorption rate on the substrate.

According to one embodiment, an evaporator for generating the vapor ofan organic solvent is provided. The evaporator includes a fluid tube, aliquid organic solvent supply unit for supplying the liquid of theorganic solvent to one end of the fluid tube, and a heating unit forheating the fluid tube. The fluid tube has a cross section thatincreases from one end to the other end. The liquid of the organicsolvent is supplied to one end of the fluid tube and is heated to allowthe organic solvent vapor to discharge from the other end of the fluidtube.

In such an evaporator, since the liquid organic solvent supplied to oneend of the fluid tube is not mixed with an inert gas, the concentrationof the organic solvent vapor generated within the fluid tube can beincreased. Moreover, the fluid tube is configured in such a manner thatits cross section increases from one end to the other end, that is, fromthe upstream to the downstream side. Thus, even when the liquid organicsolvent which is not mixed with inert gas evaporates and increases involume within the fluid tube, the thermal efficiency of the organicsolvent can be maximized in various states (the liquid state, the mixedstate of liquid and vapor, and the vapor state). Accordingly, it ispossible to efficiently heat the organic solvent.

In one embodiment, the fluid tube may have a first fluid tube part witha first cross section, and a second fluid tube part with a second crosssection larger than the first cross section. The organic solvent mayinclude isopropyl alcohol and the fluid tube may have a helical shape,in this embodiment.

In another embodiment, the evaporator may further include an inert gassupply device for supplying an inert gas to the fluid tube. The organicsolvent vapor and the inert gas in a mixed state can be discharged fromthe end of the fluid tube. The inert gas may be nitrogen gas. Herein,when the organic solvent vapor is condensed on the substrate, the volumeof the organic solvent will reduce, thereby suddenly lowering theinternal pressure of the drying chamber. When the pressure is suddenlylowered, it is necessary to make the drying chamber and chamber internalmembers strongly resistant to pressure changes. However, according tothe above-described evaporator, the mixing of the organic solvent vaporwith a predetermined amount of inert gas inhibits the sudden pressurelowering caused by the condensation of the organic solvent.

In another embodiment, the evaporator may further include a purginginert gas supply device for supplying the inert gas to the one end ofthe fluid tube. The inert gas supplied from the purging inert gas supplydevice to the fluid tube discharges the remaining organic solvent fromthe other end of the fluid tube. The inert gas may be nitrogen gas. Insuch an evaporator, after generating the organic solvent vapor throughevaporation, the inert gas is supplied to one end of the fluid tube, andthe remaining organic solvent is discharged from the other end of thefluid tube by the inert gas. Therefore, after the evaporator finishesgenerating the organic solvent vapor, the inside of the fluid tube maybe clean.

The heating unit may include a lamp heater, an induction-heating typeheater, or a resistance-heating type heater.

In another embodiment, the evaporation method for generating the organicsolvent vapor includes preparing a fluid tube which has a cross sectionthat increases from one end to the other, supplying organic solventliquid to one end of the fluid tube, and evaporating the organic solventliquid by heating the fluid tube, thereby discharging the organicsolvent vapor.

In this evaporation method, since the organic solvent liquid supplied toone end of the fluid tube is not mixed with an inert gas, theconcentration of the organic solvent vapor generated within the fluidtube can be increased. Moreover, the fluid tube is configured in such amanner that its cross section increases from one end to the other end,that is, from the upstream to the downstream side. Thus, even as organicsolvent liquid not mixed with an inert gas are heated and evaporates,and its volume expands within the fluid tube, the thermal efficiency canbe maximized in various states (the liquid state, the mixed state ofliquid and vapor, and the vapor state). Accordingly, it is possible toefficiently heat the organic solvent.

The organic solvent may include isopropyl alcohol and the organicsolvent vapor may be discharged from the other end of the fluid tube ina mixed state with the inert gas by supplying the inert gas to the fluidtube. Herein, when the organic solvent vapor is condensed on thesubstrate, the volume of the organic solvent may suddenly reduce,thereby lowering the internal pressure of the drying chamber. When thepressure is suddenly lowered, it is necessary to make the drying chamberand chamber internal members strongly resistant to pressure changes.However, according to the above-described evaporation method, mixing ofthe organic solvent vapor with a predetermined amount of inert gas mayinhibit the sudden pressure lowering caused by the condensation of theorganic solvent.

The inert gas may be supplied to one end of the fluid tube, dischargingthe organic solvent remaining within the fluid tube from the other endof the fluid tube, after evaporating the organic solvent liquid andgenerating the organic solvent vapor. Therefore, according to theevaporation method, after generating the organic solvent vapor, theinside of the fluid tube may be clean.

In another embodiment, a substrate processing apparatus for processing asubstrate is provided. The substrate processing apparatus includes theabove-described evaporator, and a chamber for receiving the substrateand drying the received substrate. The chamber is supplied with organicsolvent vapor generated by the evaporator. In such a substrateprocessing apparatus, by increasing the concentration of organic solventvapor generated by the evaporator, the adsorption rate of organicsolvent vapor on the substrate increases. Thus, the drying time of thesubstrate may be shortened, thereby reducing the usage amount of theorganic solvent.

According to the evaporator and evaporation method of the presentinvention, the concentration of generated organic solvent vapor can beincreased and the organic solvent can be heated efficiently.

In addition, according to the substrate processing apparatus of thepresent invention, the adsorption rate of organic solvent vapor on thesubstrate increases. Thus, the drying time of the substrate may beshortened, thereby reducing the usage amount of the organic solvent.

Hereinafter, an illustrative embodiment of the present invention will bedescribed with reference to the accompanying drawings. First, anevaporator according to the present embodiment will be described indetail. Herein, FIG. 1 through 4 show an evaporator according to thepresent embodiment. Specifically, FIG. 1 schematically illustrates theevaporator according to the present embodiment, and FIG. 2 shows theconfiguration of the evaporator as shown in FIG. 1. FIG. 3 schematicallyillustrates another configuration of a heating unit of the evaporatoraccording to the present embodiment, and FIG. 4 schematicallyillustrates a further configuration of a heating unit of the evaporatoraccording to the present embodiment.

An evaporator 10 according to the present embodiment evaporates theliquid of a volatile organic solvent, such as isopropyl alcohol (IPA),by applying heat, thereby generating the organic solvent vapor. As shownin FIG. 2, evaporator 10 includes a cylindrical vessel 12, and fluidtubes 14, 16, and 18 provided within cylindrical vessel 12, throughwhich flows the organic solvent to be heated. Halogen lamp heaters(heating units) 20, 22, and 24 for heating fluid tubes 14, 16, and 18,respectively, are provided within cylindrical vessel 12. Hereinafter,respective elements of evaporator 10 will be described in detail.

As shown in FIG. 2, three fluid tubes 14, 16, and 18 are arrangedin-line within cylindrical vessel 12 of evaporator 10. A connecting pipe15 is provided between fluid tubes 14 and 16, and a connecting pipe 17is provided between fluid tubes 16 and 18.

Each of the fluid tubes 14, 16, and 18 surrounds corresponding halogenlamp heaters 20, 22, and 24. Fluid tubes 14, 16, and 18 have a helicalshape, the center of which approximately coincides with the center ofhalogen lamp heaters 20, 22, and 24. The shapes of fluid tubes 14, 16,and 18 are not limited to a helical shape, and the fluid tubes may havean extending straight-line type shape. Each of the fluid tubes 14, 16,and 18 may be made of stainless steel. Herein, three fluid tubes 14, 16,and 18 are disposed in order from the upstream to downstream end. Theorganic solvent liquid is supplied to fluid tube 14, and then flows fromfluid tube 14 to fluid tube 16, and fluid tube 18 in order (in otherwords, the organic solvent liquid flows from the left side to the rightside in FIG. 2). Herein, halogen lamp heaters 20, 22, and 24 heat fluidtubes 14, 16, and 18, respectively, and thereby the organic solventliquid evaporates into the organic solvent vapor. Then, the organicsolvent vapor is discharged from fluid tube 18.

Among three fluid tube 14, 16, and 18, fluid tube 14 in the mostupstream side has a smaller diameter than fluid tube 16, connected tothe downstream end of fluid tube 14. Also, fluid tube 16, connected tofluid tube 14, has a smaller diameter than fluid tube 18, connected tothe downstream side of fluid tube 16. More specifically, for example,fluid tube 14 has a diameter of about ⅛ inch, fluid tube 16 has adiameter of about ¼ inch, and fluid tube 18 has a diameter of about ⅜inch. In this manner, fluid tubes 14, 16, and 18 are configured suchthat the cross section increases from the upstream to the downstreamside.

In three fluid tubes 14, 16, and 18, the organic solvent flowing withinfluid tube 14 is substantially in a liquid state, the organic solventflowing within fluid tube 16 is in a liquid-vapor mixed state, and theorganic solvent flowing within fluid tube 18 is substantially in a vaporstate. As such, the diameters of fluid tubes 14, 16, and 18 are set sothat the cross sections of the tubes correspond to the volumes of theorganic solvent states flowing within the tubes. Thus, the organicsolvent is efficiently heated in each of fluid tubes 14, 16, and 18.

The fluid tubes are not limited to the above-mentioned three fluid tubes14, 16, and 18. Another example for the fluid tube may include afolding-fan shape whose cross section gradually increases in thedownstream direction.

Halogen lamp heaters 20, 22, and 24 are surrounded by helical fluidtubes 14, 16, and 18, respectively, and extend almost rectilinearlyalong the lengthwise direction of cylindrical vessel 12 (the horizontaldirection in FIG. 2).

As shown in FIG. 2, a heat insulator 26 is attached on the innercircumferential surface of cylindrical vessel 12. Also, both opening endportions of cylindrical vessel 12 are blocked up by end members 12 a and12 b with heat insulator 26 attached thereto.

As shown in FIG. 2, the upstream end portion of fluid tube 14 penetratesone end member 12 a of cylindrical vessel 12, thereby forming an inlet34 for the fluid. Also, the downstream end portion of fluid tube 18penetrates the other end member 12 b of cylindrical vessel 12, therebyforming an outlet 36 for the fluid. Then, the fluid transferred intocylindrical vessel 12 through inlet 34 flows through fluid tubes 14, 16,and 18, in order, and is discharged through outlet 36.

Inlet 34 is connected to a liquid organic solvent supply tube 30 a,which is connected to a liquid organic solvent supply source 30. Theliquid organic solvent is sent from liquid organic solvent supply source30 to inlet 34 via liquid organic solvent supply tube 30 a. As shown inFIG. 2, liquid organic solvent supply tube 30 a has a valve 30 binterposed therein, and valve 30 b controls the supply of the organicsolvent liquid from liquid organic solvent supply source 30 to inlet 34.Liquid organic solvent supply source 30, liquid organic solvent supplytube 30 a, and valve 30 b constitute a liquid organic solvent supplydevice for supplying the organic solvent liquid to fluid tube 14 viainlet 34.

An inert gas supply source 32 for supplying an inert gas, such as N2 gas(nitrogen gas) is provided. Inert gas supply source 32 is connected toan inert gas supply tube 32 a. Inert gas supply tube 32 a branches offinto a first branch tube 32 b and a second branch tube 32 c. Firstbranch tube 32 b is connected to liquid organic solvent supply tube 30a. As shown in FIG. 2, first branch tube 32 b has a valve 32 dinterposed therein, and valve 32 d controls the supply of the inert gasfrom inert gas supply source 32 to liquid organic solvent supply tube 30a. Meanwhile, second branch tube 32 c branches off from inert gas supplytube 32 a and connects to a connecting pipe 17 between fluid tubes 16and 18.

Herein, inert gas supply source 32, inert gas supply tube 32 a, andsecond branch tube 32 c constitute an inert gas supply device forsupplying the inert gas to connecting pipe 17. When the organic solventliquid is supplied from liquid organic solvent supply source 30 to inlet34, the inert gas is supplied from inert gas supply source 32 toconnecting pipe 17 thereby mixing with the organic solvent vapor inconnecting pipe 17. The mixed fluid of organic solvent vapor and inertgas is then sent to fluid tube 18, and is finally discharged from outlet36.

Inert gas supply source 32, inert gas supply tube 32 a, first branchtube 32 b, and valve 32 d constitute a purging inert gas supply devicefor supplying the inert gas to fluid tube 14 via inlet 34. Aftergenerating the organic solvent vapor by evaporating the organic solventliquid, valve 32 d is opened, thereby supplying inert gas to fluid tube14 via inlet 34. Through this inert gas, the organic solvent remainingwithin fluid tubes 14, 16, and 18 is discharged from fluid tube 18 viaoutlet 36. The above mentioned purging inert gas supply device removesthe organic solvent remaining within fluid tubes 14, 16, and 18, andkeeps the inside of fluid tubes 14, 16, and 18 clean.

While discharging the organic solvent remaining within fluid tubes 14,16, and 18, inert gas from inert gas supply source 32 may be sent toboth first branch tube 32 b and second branch tube 32 c. The organicsolvent remaining within fluid tubes 14, 16, and 18 is discharged by theinert gas. Each of halogen lamp heaters 20, 22, and 24 may heat theinert gas passing through the inside of each of fluid tubes 14, 16, and18, and the heated inert gas is discharged from outlet 36 into a chamberof a substrate processing apparatus (which will be described later).

In order to heat and transfer the inert gas into the chamber of thesubstrate processing apparatus, the following method may also be used.First, valve 32 d is opened to supply the inert gas to fluid tube 14 viainlet 34, discharging the organic solvent remaining within fluid tubes14, 16, and 18 via outlet 36 by the inert gas. Next, valve 32 d isclosed, thereby supplying the inert gas connecting pipe 17 from inertgas supply source 32 via second branch tube 32 c. Halogen lamp heater 24heats the inert gas passing through the inside of fluid tube 18, and theheated inert gas is discharged from outlet 36. In this case, whileheating the inert gas, halogen lamp heaters 20 and 22 may be turned off,reducing the consumption of power.

An additional valve may be interposed in second branch tube 32 c. In thecase where the valve is provided in second branch tube 32 c, when theinert gas is not supplied to connecting pipe 17 via second branch tube32 c from inert gas supply source (32), closing the valve may preventthe organic solvent vapor from flowing into second branch tube 32 c orinert gas supply tube 32 a from connecting pipe 17.

According to the evaporator of the present embodiment, the heating unitfor fluid tubes 14, 16 and 18 is not limited to halogen lamp heater 20,22, and 24 as shown in FIG. 2. For example, as shown in FIG. 3, aninduction-heating type heater may be used. Herein, fluid tube 14 fromamong three fluid tubes 14, 16, and 18 is provided as an example. InFIG. 3, fluid tube 14 is helical, made of stainless steel, andsurrounded by a coil 52 with an insulator 50 interposed between helicalfluid tube 14 and coil 52. High frequency power is applied to coil 52 bya high frequency power supply 54, inducing electromotive force inhelical fluid tube 14 in a direction (to the left in FIG. 3) against tothe magnetic field of coil 52. The induced current in fluid tube 14 thenproduces Joule heating. Fluid tube 14 may be heated by the Jouleheating. In this manner, an induction-heating type heater including coil52 and high frequency power supply 54 may be used to heat fluid tube 14.

As another example of a heating unit for fluid tubes 14, 16, and 18, aresistance-heating type heater may be used, as shown in FIG. 4. Herein,fluid tube 14 from among three fluid tubes 14, 16, and 18 is shown as anexample. Fluid tube 14, extending almost rectilinearly, is surrounded bya resistance-heating type heater 56, such as a band-type ribbon heater,rubber heater, or tube-type ceramic heater. Resistance-heating typeheater 56 causes electric current to flow in a heating conductor 56 a,such as nichrome wire, thereby generating heat. Herein, even thoughresistance-heating type heater 56 is wound around fluid tube 14, a gapmay occur between fluid tube 14 and resistance-heating type heater 56.For this reason a thermally conductive member 58 may be provided.

Hereinafter, the operation of evaporator 10 as shown in FIGS. 1 and 2will be described.

First, when the valve 30 b is opened, liquid organic solvent supplysource 30 supplies liquid organic solvent to inlet 34 via liquid organicsolvent supply tube 30 a. Then, halogen lamp heaters 20, 22, and 24 heatfluid tubes 14, 16, and 18, respectively. Inert gas supply source 32supplies inert gas to connecting pipe 17 via inert gas supply tube 32 aand second branch tube 32 c. At this time, valve 32 d is closed.

The organic solvent liquid sent to fluid tube 14 is heated within fluidtube 14. Herein, the organic solvent is in a liquid state within fluidtube 14. The heated organic solvent liquid is sent to fluid tube 16 viaconnecting pipe 15, and is further heated within fluid tube 16. Herein,the organic solvent is in a liquid-vapor mixed state at the upstreamarea of fluid tube 16, and the organic solvent is in a vapor state atthe downstream area of fluid tube 16 (see FIG. 1).

In connecting pipe 17, the organic solvent vapor from fluid tube 16, andthe inert gas from second branch tube 32 c are mixed with each other.The mixed fluid of organic solvent vapor and inert gas is sent to fluidtube 18, and further heated within fluid tube 18. Herein, the organicsolvent is in a vapor state within fluid tube 18. Then, the mixed fluidof organic solvent vapor and inert gas is discharged via outlet 36.

As described above, after the process of generating the organic solventvapor by evaporation of the organic solvent liquid, in order to removethe excess organic solvent from fluid tubes 14, 16, and 18, valve 32 dis opened to supply the inert gas to inlet 34 from inert gas supplysource 32 via inert gas supply tube 32 a and first branch tube 32 b. Theinert gas discharges the remaining organic solvent within fluid tubes14, 16, and 18 from fluid tube 18 via outlet 36. In this manner, theremaining organic solvent within fluid tubes 14, 16, and 18 are removedand the inside of fluid tubes 14, 16, and 18 remain clean.

As described above, according to evaporator 10 and the evaporationmethod of the present embodiment, since the organic solvent liquidsupplied to fluid tube 14 is not mixed with the inert gas, theconcentration of the organic solvent vapor generated within fluid tubes14, 16, and 18 can be increased. Fluid tubes 14, 16, and 18 areconfigured in such a manner that their cross sections increase from oneend to the other end (that is, from the upper stream side to the lowerstream side). Accordingly, during the evaporation process the organicsolvent liquid is not mixed with the inert gas within fluid tubes 14 and16, and even though the volume of the organic solvent increases, it ispossible to increase the thermal efficiency of the organic solvent invarious states, such as in the liquid state, the mixed state of liquidand vapor, and the vapor state (see FIG. 1). Accordingly, the organicsolvent can be efficiently heated.

The inert gas is supplied to connecting pipe 17 between fluid tubes 16and 18, and the mixed organic solvent vapor and inert gas are dischargedfrom outlet 36 on the downstream side of fluid tube 18. Herein, when theorganic solvent vapor is condensed on a wafer W, the volume of theorganic solvent will decrease, thereby suddenly lowering the pressurewithin the chamber of the substrate processing apparatus (which will bedescribed later). When the pressure is lowered, it is necessary to makethe chamber or chamber internal members strongly resistant to pressurechanges. However, according to the above-described method, mixing theorganic solvent vapor with a predetermined amount of inert gas inhibitsthe sudden pressure lowering caused by the condensation of the organicsolvent.

Also, after the process of generating the organic solvent vapor byevaporating the organic solvent liquid, the inert gas is supplied toinlet 34 on the upstream portion of fluid tube 14. Due to the inert gas,the organic solvent remaining within fluid tubes 14, 16, and 18 isdischarged from outlet 36 at the downstream portion of fluid tube 18.Accordingly, after the generation of the organic solvent vapor byevaporator 10, when the use of evaporator 10 is finished, the inside offluid tubes 14, 16 and 18 are kept clean.

Hereinafter, a substrate processing apparatus 60 including evaporator 10as shown in FIG. 1 will be described with reference to FIG. 5. FIG. 5schematically shows the configuration of substrate processing apparatus60 according to one embodiment of the present invention.

Substrate processing apparatus 60, as shown in FIG. 5, includes a liquidtreatment unit 62 for performing chemical-solution treatment or awashing process on a wafer W, and a drying unit 61, provided at theupper side of liquid treatment unit 62, for drying wafer W aftersubjecting it to the washing process in liquid treatment unit 62.Herein, liquid treatment unit 62 is set to treat wafer W with apredetermined chemical solution [for example, diluted hydrofluoric acid(DHF), ammonia-hydrogen peroxide mixture (APF), sulfuric acid-hydrogenperoxide mixture (SPM)], and to then perform the washing process bydeionized water (DIW). Substrate processing apparatus 60 may include awafer guide 64 capable of holding multiple (for example, 50) wafers W.Wafer guide 64 is movable (upward/downward) between liquid treatmentunit 62 and drying unit 61. Above substrate processing apparatus 60, afan filter unit (FFU, not shown) is disposed, which supplies clean airto substrate processing apparatus 60 as down flow.

As shown in FIG. 5, liquid treatment unit 62 includes a reservoir 69 forstoring the chemical solution or DIW. The chemical solution and DIW arealternately stored in reservoir 69, and the chemical-solution treatmentor washing process of wafer W can be carried out by immersing wafer W inthe chemical solution or DIW, respectively.

Drying unit 61 includes a chamber 65 for receiving wafer W, and achamber wall 67, which forms chamber 65 therein.

The atmospheres around reservoir 69, and chamber 65 can be separatedfrom or can communicate with each other by a horizontally slidableshutter 63, disposed between reservoir 69 and chamber 65. When liquidtreatment is performed in reservoir 69 of liquid treatment unit 62, orwhen wafer guide 64 moves wafer W between reservoir 69 and chamber 65,shutter 63 is housed in a shutter box 66, thereby communicating theatmosphere around reservoir 69 with the atmosphere of chamber 65.Otherwise, when shutter 63 is disposed beneath chamber 65, a seal ring63 a, provided on the top surface of shutter 63, contacts the lower endof chamber wall 67, tightly blocking up the bottom opening of chamber65.

A fluid nozzle 70 that supplies water vapor, IPA (isopropyl alcohol)vapor, or mixture thereof into chamber 65 is disposed within chamber 65.Fluid nozzle 70 is connected to a pipe 80, which branches off into pipes80 a and 80 b. The branched-off pipes are connected to a DIW supplysource 91 and an IPA supply source 92, respectively. A predeterminedamount of DIW is sent to a heater 87 by opening an open/close valve 82provided on pipe 80 a, and controlling a flow control valve 85. Then,DIW is heated in heater 87, thereby generating water vapor. Likewise, apredetermined amount of liquid of IPA is sent to evaporator 10 byopening an open/close valve 83 provided on pipe 80 b, and controlling aflow control valve 86. The liquid IPA is heated in evaporator 10,thereby generating IPA vapor. The water vapor, IPA vapor, or mixturethereof (which is mixed in pipe 80) is sprayed into chamber 65 fromfluid nozzle 70.

An N2 gas nozzle 71 for spraying N2 gas (nitrogen gas), heated to apredetermined temperature, to chamber 65 is provided within chamber 65.As shown in FIG. 5, N2 gas in room temperature is supplied from an N2gas supply source 93 to a heater 88 by releasing an open/close valve 84.The N2 gas is heated to a predetermined temperature by heater 88, andthe heated N2 gas is sprayed into chamber 65 from N2 gas nozzle 71 viaan N2 gas supply line 81.

A gas exhaust nozzle 72, for discharging atmospheric gas within chamber65, is disposed within chamber 65. Gas exhaust nozzle 72 includes anatural gas exhaust line for performing natural gas exhaustion from theinside of chamber 65, and a forced gas exhaust line for performingforced gas exhaustion from the inside of chamber 65.

Hereinafter, a method for processing a wafer W using the above-describedsubstrate processing apparatus 60 will be described.

First, shutter 63 separates reservoir 69 of liquid treatment unit 62 andchamber 65 of drying unit 61 from each other. Also, the inside ofchamber 65 is filled with N2 gas, and the internal pressure is set to beequal to atmospheric pressure. Meanwhile, a predetermined chemicalsolution is stored in reservoir 69, while wafer guide 64 is disposedwithin chamber 65 of drying unit 61.

Then, the supply of N2 gas into chamber 65 is stopped, and 50 wafers Ware transferred from an external substrate-carrying device (not shown)to wafer guide 64. Next, forced gas exhaustion is performed from gasexhaust nozzle 72, while shutter 63 is slid such that reservoir 69 andchamber 65 communicate with each other.

Wafer guide 64 is then moved down, thereby immersing the held wafer W inthe chemical solution stored in reservoir 69 for a predetermined timeperiod. After the completing the chemical solution treatment of wafer W,it is immersed in reservoir 69, while DIW is fed into the reservoir,replacing the chemical solution, and washing wafer W. The replacement ofthe chemical solution by the DIW in reservoir 69 may occur bydischarging the chemical solution via a drainage tube 69 a from, andthen supplying the DIW to reservoir 69.

After completing the chemical solution treatment and washing process ofwafer W, the gas exhaust from chamber 65 is converted from the forcedgas exhaust line into the natural gas exhaust line. N2 gas nozzle 71supplies N2 gas, heated to a predetermined temperature to chamber 65,and maintains an atmosphere of, heated N2 gas in chamber 65. This warmsup the inside of chamber 65 and chamber wall 67, so that when IPA vaporis supplied into chamber 65 later, dew condensation of the IPA vapor onchamber wall 67 is inhibited.

After the supply of the heated N2 gas into chamber 65, fluid nozzle 70supplies water vapor, filling the inside of chamber 65 with water vaporatmosphere. Then, in order to receive wafer W within chamber 65, waferguide 64 begins to be pulled up. Wafer W is not dried during beingpulled up to the space filled with water vapor, and thus watermarks arenot formed on wafer W.

Wafer guide 64 is stopped once wafer W is housed in chamber 65, andshutter 63 is closed to separate reservoir 69 and chamber 65 from eachother. Also, when wafer W reaches a predetermined position withinchamber 65, fluid nozzle 70 introduces IPA vapor into chamber 65. Thus,IPA replaces DIW on the surface of wafer W. Herein, since the surfacetension of the liquid on wafer W changes slowly, the liquid filmthickness is uniform. Also, since the balance of surface tension appliedto the convex portion of the circuit pattern on wafer W is not easilylost, it is possible to avoid the occurrence of pattern collapse.Finally, the surface of wafer W is dried substantially at the same time,thereby suppressing the formation of watermarks.

Once an IPA liquid film is formed on the surface of wafer W aftersupplying the IPA vapor for a predetermined time period, the supply ofthe IPA vapor into chamber 65 is stopped and wafer W is dried through adrying process. For example, the drying process may include evaporatingIPA from the surface of wafer W by supplying N2 gas heated up to apredetermined temperature into chamber 65, and cooling wafer W down to apredetermined temperature by supplying with N2 gas at room temperatureinto chamber 65.

In such a drying process, IPA on the surface of wafer W can be uniformlyevaporated. Thus, the balance of surface tension applied to the convexportion of a circuit pattern on wafer W is not easily lost, whichinhibits the occurrence of pattern collapse. Also, since wafer W isdried from a state where only IPA exists on the surface, the formationof watermarks is prevented.

When the drying process of wafer W is completed, a substrate-carryingdevice (not shown) from outside accesses wafer guide 64 to take outwafer W from substrate processing apparatus 60. In this manner, a seriesof processes on wafer W in substrate processing apparatus 60 arecompleted.

The above-described substrate processing apparatus 60 includesevaporator 10 as shown in FIG. 1, and thus can increase concentration ofIPA vapor generated by evaporator 10. For this reason, the adsorptionrate of IPA vapor on wafer W increases, shortening drying time of waferW, and reducing the usage amount of IPA.

From the foregoing, it is noted that various embodiments of the presentdisclosure have been described herein for purposes of illustration, andthat various modifications may be made without departing from the scopeand spirit of the present disclosure. Accordingly, the variousembodiments disclosed herein are not intended to be limiting, with thetrue scope and spirit being indicated by the following claims.

1. An evaporator for evaporating an organic solvent comprising: a fluidtube including at least a first fluid tube part and a second fluid tubepart, each of the first fluid tube part and the second fluid tube partbeing a helical shape, and the second fluid tube part being connected ata downstream side of the first fluid tube part through connecting pipe;a liquid organic solvent supply device configured to supply only organicsolvent liquid to one end of the first fluid tube part; and a heatingunit disposed inside each of the helical shape of the first fluid tubepart and the second fluid tube part in such a way that the center of theheating unit approximately coincides with the center of the first fluidtube part and the second fluid tube part, and configured to heat each ofthe first fluid tube part and the second fluid tube part independentlysuch that the organic solvent liquid is maintained substantially at aliquid state in the first fluid tube part and at a liquid/vapor mixedstate in the second fluid tube part, wherein the first fluid tube partis designed to have a first cross section suitable for the liquid stateand the second fluid tube part is designed to have a second crosssection larger than the first cross section suitable for theliquid/vapor mixed state, and the organic solvent liquid supplied to theone end of the second fluid tube part is heated to be discharged as anorganic solvent vapor from the other end of the second fluid tube partwithout being mixed with an inert gas.
 2. The evaporator as claimed inclaim 1, wherein the fluid tube further comprises: a third fluid tubepart connected at a downstream side of the second fluid tube part havinga third cross section larger than the second cross section, wherein thethird fluid tube part is heated independently such that the vapor stateorganic solvent supplied from the second fluid tube part is maintainedat a vapor state in the third fluid tube part and the organic solventvapor is discharged from a downstream side of the third fluid tube part.3. The evaporator as claimed in claim 2, further comprising an inert gassupply device connected between the second fluid tube part and the thirdfluid tube part, and configured to supply an inert gas to the thirdfluid tube part, wherein the organic solvent vapor and the inert gas aredischarged in a mixed state from the other end of the third fluid tubepart.
 4. The evaporator as claimed in claim 3, wherein the inert gas isnitrogen gas.
 5. The evaporator as claimed in claim 3, furthercomprising a purging inert gas supply device to supply the inert gas tothe one end of the fluid tube, wherein the inert gas supplied from thepurging inert gas supply device to the fluid tube discharges the organicsolvent remaining within the fluid tube from the fluid tube.
 6. Theevaporator as claimed in claim 5, wherein the inert gas is nitrogen gas.7. The evaporator as claimed in claim 1, wherein the organic solventcomprises isopropyl alcohol.
 8. The evaporator as claimed in claim 1,wherein the heating unit comprises a lamp heater.
 9. The evaporator asclaimed in claim 1, wherein the heating unit comprises aninduction-heating type heater.
 10. The evaporator as claimed in claim 1,wherein the heating unit comprises a resistance-heating type heater. 11.A substrate processing apparatus for processing a substrate, thesubstrate processing apparatus comprising: the evaporator as claimed inclaim 1; and a chamber for receiving the substrate and drying thereceived substrate, wherein the chamber is supplied with organic solventvapor generated by the evaporator.